'Cause when the tears start flowin' and the wind starts blowin'
That's how you know it's comin' for you
When the rain starts fallin' and you feel the pain comin'
That's how you know it's comin' for you

"After the Hurricane," Jazmine Sullivan

No relationship is bright and sunny at all times, but it is definitely not a good sign when you haven't seen the sun in a while. Here are some common warning signs that you should definitely not ignore:

Lack of Interest

If you finish a long-winded, three-minute spiel about how stressful your day was, or how interesting the panel on healthcare that you've been waiting weeks to go to was, and he’s not even looking at you—let alone offering some sort of sympathy—that's a serious problem. Other way around: If he doesn't confide in you anymore or tell you about his day and activities, that's also a flashing red light. You two don't have to be best friends, but if you aren't communicating with each other, what’s the point? And yes, the romantic hoopla may die down after a relationship has been going on for some time, but you should not always be the one initiating dates, phone calls, or conversations. Maybe he's just more comfortable with you doing it, but if he doesn't have a good reason, he may have lost interest and doesn't know how to convey it.

Shadiness

This is sort of a give-in, but if one day he randomly refuses to let you play Tap Tap Revenge 2 on his iPhone, you're treading murky waters. Being very secretive about your phone, or social applications like Facebook and Twitter, should definitely raise an eyebrow. Similarly, if you're constantly being kept out of the loop about where he's going or why you can't come with, and if he makes a big deal if you ask, there might be something going on. I'm not saying that he's cheating, but if he actively gives you reason to question his behavior, either call him out on it, or just keep your eyes open.

Different Goals

Sometimes couples just aren't mentally in the same place. You both don't have to want to do the same thing, but if you always talk about how you want to be president of your club and he's just trying to make more friends in Sims 3, you might want to consider how this will play out in the long term. Your significant other should complement you and be supportive, not bring you down. Also, if you know that your future plans are drastically different, you very well may be wasting your time. He can't settle down in his hometown and get married a couple years after graduation if you're planning to spend the next fifteen years doing missionary work in Uganda.

Constant Bickering

This is always the deal breaker: arguing day and night, all the time, about the same things. If you constantly bring up matters of the past, such as how he forgot your little brother's birthday last November, one of you is going to lose it. Talk about it one time, and then just move on. If your arguments have to do with one of your friends or family members not approving of the relationship, it makes the situation a bit harder. You both should discuss how important the person's opinions are, why they feel the way they do, and if there is a way for their mind to be changed. If it turns out to be unimportant, just brush it off, and make sure not to bring it up in a cheap shot while you two are arguing about something else.

If you find yourself arguing over and over, try this. Take a sheet of paper and draw a line down the middle. On one side, list everything you like about the other person, from the ways they fold their socks to the way their smile makes your day. On the other side, write down everything that you don't like. Search deep, and make the list comprehensive. Then assign points to the things you listed based on how important they are; for example, their socks might get a 1, while their smile gets a 3. Then sum up both columns; if the negative column is more that the positive one, you might want to take a break and reevaluate things, or break up entirely. If the positive column is more than the negative one, then you both just might need to put the relationship into perspective, discuss feasible solutions to the main problems, and let the minor issues go. Don't let stormy clouds linger over your paradise for too long because a hurricane may begin; either move to another island, or make the sun come out again.

Source: http://www.flyguychronicles.com/2008/08/the-top-5-relationship-killers/